use warnings;
use strict;
use Test::More tests=>4;

my $str = "##############################################################################\r\n# This system is a restricted access system.                                 #\r\n# If collected security information reveals possible criminal activity that  #\r\n# exceeds privileges, evidence of such activity may be provided to the rele- #\r\n# vant authorities for further action. By continuing past this point, you    #\r\n# expressly consent to this security monitoring.                             #\r\n##############################################################################\r\n\r\nhostname: ~# ";

my $re1 = qr{(([#%:>~\$\] ])(?!\2)){3,4}|([\w\-\.]*)\$ *$|\w[@\/]\w.*?[#%>~\$\]]|^[#%\$>\:]~] *$};
my $re2 = qr{(([#%:>~\$\] ])(?!\2)){3,4}|([\w\-\.]*)\$ *$|(\w[@\/]\w|sftp).*?[#%>~\$\]]|^[#%\$>\:]~] *$};

ok $str =~ $re1;
is $&, ": ~#";
ok $str =~ $re2;
is $&, ": ~#";